1. Field of the Invention
This invention relates to foil perforating apparatus of the type which includes a foil holder and a foil perforating means which are movable relative to each other. Such foil perforating apparatus are used to produce an image carrier for a component-mounting pattern adapted to be projected onto a printed wiring board to which components are to be attached.
2. Description of the Prior Art
From German patent application DT-AS 24 59 480.7, it is known to use, as an image carrier for a component-mounting pattern to be projected onto a printed wiring board to which components are to be attached, a foil of an opaque material provided with perforations representing component-insertion symbols. That German application states that an apparatus constructed in the manner outlined above may be used for perforating the foil.
It has been found that with prior-art apparatus of this type there is some uncertainty with regard to the accuracy of perforation since a shift, though slight, may occur between the foil holder and the perforating means during the perforation operation. Now when the foil is subsequently used as an image carrier in a projector, even slight shifts will result in fairly large deviations of the projected image on the printed wiring board to which components are to be attached.